Abstract This application is for a planning grant to develop an RCT to test the impact of standardized portions in away-from home settings. Given that restaurants all serve different portions and generally serve more food than most customers can burn, making portions standardized and predictable could help millions of Americans control how much they eat and reduce their risk for overweight and obesity. We plan to establish what standard portion sizes should be for different items; develop practical methods by which restaurants could adopt these standard portions and conduct a pilot test in these 3 restaurants to assess consumer interest as well as to develop and test recruitment methods and measurement of customer participants. The establishment of standardized portion sizes will serve as an aspirational benchmark for the food industry to comply with recommendations from the USDHHS/USDA Dietary Guidelines of Americans and will provide guidance for consumers. An implementation plan, informed by restaurateurs and consumers, is necessary for a rigorous RCT, which would need to enroll many restaurants and their customers. In this planning grant our specific aims are to: 1) Develop a consensus among health and nutrition experts as to what the standardized portion amounts should be and how they should be measured (e.g. weights, volumes, and relevance of calories). 2) Pilot test and refine a training in three restaurants to examine the feasibility of adopting the standardized portions and adherence to the recommended standards. 3) Pilot recruitment and measurement methods for customers, including assessing response rates, perceptions of standardized portions, and 24-hour dietary recall methods. Once these aims have been accomplished, we will have obtained the information necessary for powering and conducting a rigorous RCT that would ultimately determine the impact of standardized portions sizes on diet, and specifically on how standard portions will influence the consumption of nutrients of consequence to cardiovascular health, especially reducing exposure to refined grains, starches, sugars, processed meats, high sodium foods, and increasing consumption of fruits, vegetables, fish, vegetable oils, nuts, low-fat dairy, and whole grains.